Nonsteroidal anti-inflammatory drugs such as lysozyme chloride and the like have been effective for the amelioration of initial symptoms and acute inflammations of rheumatism but ineffective for the improvement of progressed conditions of chronic rheumatism with bone destructions, or for the treatment of bone osteoarthritis and the like. Further, the conventional drugs might cause gastric ulcer because of their strong actions.
Recently, it has become apparent that leukotrienes (LT), especially LTB.sub.4 and the like, which are metabolic products in the metabolic pathway of arachidonic acid with 5-lipoxygenase, are important mediators of inflammatory reactions. It is also suggested that interleukin-1 (IL-1) being one type of cytokines is responsible for inflammation, greatly for chronic rheumatism in particular. Under the conditions above, it has been considered that the compounds which inhibit the production of both LTB.sub.4 and IL-1 are promising as antiinflammatory drugs. Such compounds are more useful than conventional nonsteroidal anti-inflammatory drugs because they are expected to be effective on not only acute inflammations but also chronic inflammations such as chronic rheumatism and the like.
Various compounds useful as anti-inflammatory drugs have been disclosed in Japanese patent Publication (KOKAI) Nos. 79944/1983, 257962/1986, 42977/1987, 305028/1989, 4729/1990, 256645/1990, 270865/1990, Japanese patent WO 89/503782 and the like. To obtain compounds which are effective for the treatment of chronic inflammations with lower side-effects such as gastric disorders, it has been continuously demanded to develop compounds which can efficiently suppress the production of mediators of inflammations such as prostaglandin E.sub.2 (PGE.sub.2), LTB.sub.4, IL-1 and the like.
The present inventors have found that a certain kind of benzylidene derivatives remarkably inhibit the production of PGE.sub.2, as well as that of cytokines such as LTB.sub.4, IL-1 and the like, and have accomplished the present invention.